Photomicrographs of VDR immunoreactivity in hippocampal cultures (7–14 DIV). A, Two representative pyramidal-shaped neurons positively stained for the VDR with Ab4707 (phase contrast optics). B, No cellular staining was observed when the VDR antibody was preincubated with its epitope.C, Cell culture double-labeled with antibodies to VDR and GFAP to determine cell-specific labeling of VDR. Most cells expressing the VDR (brown stain) were neurons, as indicated by the morphology and the lack of co-labeling with the glial marker GFAP (violet stain). D, Nuclei of astrocytes (arrow) showed either weak or no staining for the VDR. A pyramidal-shaped neuron in the field stained positively for VDR (arrowhead) is shown for comparison. Scale bars:A, B, D, 50 μm; C, 100 μm.